Shrinkage-gage



(No Model.)

H. S. BROWN.

SHRINKAGB GAGE.

No. 271.411. Patented Jan.30,1883.

'UNTTED STATES PATENT @rrrcn.

HENRY. SMITH BROWN, OF HARTFORD, CONNECTICUT.

SHRlNKAGE-GAGE.

SPECIFICATION forming part of Letters Patent No. 271,411, dated January30, 1883, Application filed August 23, 1882. (No model.)

To all whom it may concern Be it known that I, HENRY SMITH BROWN, acitizen of the United States, residing in Hartford, in the county ofHartford and State of Jonnecticut, have invented a new and usefulShrinkage-Gage, of which the following is a specification.

My'inven tion is an instrument used in measuring the interior diameterof metal cylinders and the exterior diameter of metal shafts, when sucha cylinderis to be fastened around such a shaft by means of the naturalcontraction of the cylinder, due to its gradual cooling, or by means ofthe cylinder being forced upon the shaft by hydraulic or other power.The cranks of stationary and of marine engines fastened to the shafts ofsuch engines and the wheels of locomotives and railroadcars fastened totheir axles are instances of such fasteningofmetalcylinders around metalshafts. It is well known that both these methods of fastening cylindersto shafts require that the diameter of the shaft be made somewhat largerthan the interior diameter of the cylinder; and experience has shownthat the two diameters must be proportioned to each other withextraordinary accuracy, in order, on the one hand, to prevent thecylinder from breaking because of too great strain, and, on the otherhand, to prevent it from becomiugloose because of too little contractileforce. The difference between the diameter of the shaft and the interiordiameter of the cylinder ought not to beless than one-tenth of one percent. nor more than two tenths of one per cent. when the cylinder is tobe fastened to the shaft by cooling after being expanded by heat; andwhere the cylinder is to be fastened to the shaft by pressure thedifference between the two diameters ought not to be less thanthree-fourths of one-tenth of one per cent. nor more than twice thelatter amount.

It has heretofore been practicable by the use ofcalipers to make thediameter of a shaft agree exactly with the length of a rod used tomeasure the interior diameterof the cylinder; but it has always beenimpossible to make the two measurements vary without sometimes varyingmore and sometimes varying less than the particular case admitted orrequired. By the use of my invention that highly-useful be measured withthat gage.

resnltean be accomplished with unvarying accuracy.

' My invention isillustrated in the accompanying drawings,similarletters referring to the same parts throughout the several views.

Figure 1 is a side view of my gage, as inserted in the cylinder thediameter of which is being measured by it. Fig. 2 is a central verticalsection of Fig 1. Fig. 3 is an edge view of the gage after it iswithdrawn from the cylinder and lengthened one-tenth of one per cent. bythe insertion between two of its parts of the expansion-slip 9. Fig. 4is a specimen metal expansionslip, preferably made of steel, the smallerend of which is exactly nine one-thousandths of an inch thick, andtherefore suitable for use when a nine-inch shaft is to beinserted inacorrespondingcylinder. These slips are made to conform to the exactthickness desired by the use of the Wellknown micrometer-calipers. Thenumber desirable with each gage is the same as the number of differentdiameters of cylinders to Each slip may be marked with figures showingits exact thickness, and also with other characters showing the diameterof the cylinder to which it is applicable.Asufficientvarietyofslipswillenable the operator to expand the gage tothe exact extent which the size ofthe eylinder,orthe nature of themetal, or the method of the fit ting, or his own instructions oropinions relevant to amount of desirable shrinkage, or any or all ofthese considerations, may require in each particular case.

a is a frame, one end of which is a tapering cylindrical split hub,threaded externally to receive the clamp-nut b, and threaded internallyto receive the tube 0. The tube 0 is threaded internally to receive theadjustable spindle d. The cheek-nut c is also threaded to correspondwith the thread of the spindle. The tube 0 is preferably closed at thebottom. The plngfforms a solid part of the frame a, its purpose being tofill the hole, through which, in assembling the parts of the gage, thetube 0 is inserted into the frame. The tube may, however, be constructedwith its lower portion small enough to pass through the split hub, andin that case there need be no hole in the bottom of the frame, andtherefore no plug to fill sucha hole. In that event, however, the frameshould receive a form at its lower end similar to the form of the lowerend of plug f. The top of the plug, or it no plug is used then thecorresponding part of the frame, should be ground into exact parallelismwith the bottom of the tube 0.

The operation is as follows The clamp-nut and the check-nut are loosenedand screwed back, allowing the bottom of the tube to be screwed firmlydown upon the top of theplug, and allowing the spindle to be screwed upto such an extent as will cause the whole gage to exactly measure thediameter of the cylinder into which it is inserted. Thereupon thecheck-nut is screwed home, so as to lock the spindle against the top ofthe tube, and the gage is then taken away from the cylinder, and thetube is screwed up far enough to admit an expansion-slip of therequisite thickness between the bottom of the tube and the top of theplug; and after the expansion-slip is inserted the tube is screwed downhard upon it, and the clampnnt is screwed home, so as to lock the tubewith the frame. By these operations the gage is lengthened to an extentexactly equal to the thickness of the expansion-slipinserted,anditstotal length furnishes a perfect measure by which to turn the shaft forinsertion into the cylinder. By means of ordinary machinists calipersthe diameter of the shaft being turned may be made to correspond exactlywith the length of the gage as expanded by the slip.

My shrinkage-gage may be variously moditied without changing itsessential character. A check-nut or a collar with a set-screw may besubstituted for the clamp-nut b, and if the first-mentioned substitutionis made the hub should not be split. So, also, a clamp-nut or a collarwith a set-screw may be substituted for the cheek-nut e,- but in case ofeither of those substitutions the tube 0 must be split at its upper end.These are examples of mechanical changes in my gage'which will suggestthemselves to those skilled in the art to which that instrumentpertains.

I claim as my invention- 1. The combination, in a gage, of the frame a,the clainpnut b, the tube 0, the spindle d, the check-nut c, and theexpansion-slip, substantially as described, or its equivalent.

2. The combination, in a gage, ot' the frame a, the clamp-nut I), thetube a, and the expansion-slip, substantially as described, or itsequivalent.

HENRY SMITH BROWN.

\Vitnesscs ALBERT H. WALKER, MouGAN W. BEACH.

